26 + Mcqs in Three Phase Transformer Page 1 McqOptions

1.	A recording of the output of the emf induced for star and delta are recorded. Then shape of the emf induced in Y-connected 3-phase transformer is non sinusoidal in nature due to ___________
A.	3rd harmonic component of currents is absent
B.	3rd harmonic component of currents is present
C.	negative sequence component of current is present
D.	none of the mentioned
Answer» B. 3rd harmonic component of currents is present

Discussion

2.	While using three phase transformers, it is taken care about the third harmonics current in the system. This is present when transformer set is delta on either side.
A.	True
B.	False
Answer» B. False

Discussion

3.	A 400 V, 10 KVA transformer at 50 Hz, is operated at the frequency of 40 Hz, then the humming ___________
A.	increases
B.	decreases
C.	remains same
D.	increases to very high
Answer» B. decreases

Discussion

4.	When we magnetize the ferromagnetic core of the transformer, core length_______ and it ______ when demagnetized.
A.	decreases, increases
B.	decreases, decreases
C.	increases,increases
D.	none of the mentioned
Answer» B. decreases, decreases

Discussion

5.	If para magnetic core is used in the place of the ferromagnetic core of the transformer, then magnetostriction will ___________
A.	be vanished
B.	reduce
C.	increase
D.	not be affected
Answer» B. reduce

Discussion

6.	Below is the circuit diagram for delta-delta transformer have a transformation ratio ‘k’. The current flowing in the windings of phase r-y in the below diagrams is?
A.	k*I/1.73
B.	I/k*1.73
C.	1.73kI
D.	3kI
Answer» B. I/k*1.73

Discussion

7.	If one of the transformers is removed from the bank of only delta-delta, then it behaves with 58% power delivery.
A.	True
B.	False
Answer» B. False

Discussion

8.	Open delta transformers can be obtained from ___________
A.	delta-delta
B.	star-delta
C.	delta-star
D.	any of the mentioned
Answer» B. star-delta

Discussion

9.	The delta-delta connections are used in applications of ___________
A.	large l.v. transformers
B.	small h.v. transformers
C.	large h.v. transformers
D.	small l.v. transformers
Answer» B. small h.v. transformers

Discussion

10.	The voltage across the terminal ‘r’ and ‘y’ is?
A.	1.73*V
B.	V/1.73
C.	V
D.	3*V
Answer» C. V

Discussion

11.	For the given circuit below, the voltage across the terminal ‘a’ and ‘b’ is?
A.	1.73*V
B.	V/1.73
C.	V
D.	3*V
Answer» B. V/1.73

Discussion

12.	The transformer which is more feasible to use in the distribution ends should be ___________
A.	star-delta
B.	delta-star
C.	scott
D.	delta-delta
Answer» B. delta-star

Discussion

13.	Three units of single phase transformers and one single three-phase transformer rating ___________
A.	will be same for one rating
B.	can never be made same
C.	may be same
D.	none of the mentioned
Answer» B. can never be made same

Discussion

14.	A V-V connected transformer can be connected in parallel to delta-delta connected transformer but not to ___________
A.	delta-star
B.	star-delta
C.	star-V
D.	all of the mentioned
Answer» B. star-delta

Discussion

15.	When we magnetize the ferromagnetic core of the transformer, core length_______ and it ______ when demagnetized.$
A.	decreases, increases
B.	decreases, decreases
C.	increases,increases
D.	none of the mentioned
Answer» B. decreases, decreases

Discussion

16.	If_para_magnetic_core_is_used_in_the_place_of_the_ferromagnetic_core_of_the_transformer,_then_magnetostriction_will$
A.	be vanished
B.	reduce
C.	increase
D.	not be affected
Answer» B. reduce

Discussion

17.	Shape of emf generated by delta connected transformer is not always sinusoidal.
A.	True
B.	False
Answer» C.

Discussion

18.	A recording of the output of the emf induced for star and delta are recorded.
A.
B.	3rd harmonic component of currents is absent
C.	3rd harmonic component of currents is present
Answer» B. 3rd harmonic component of currents is absent

Discussion

19.	While using three phase transformers, it is taken care about the third harmonics current in the system.
A.
B.	True
Answer» B. True

Discussion

20.	A 400 V, 10 KVA transformer at 50 Hz, is operated at the frequency of 40 Hz, then the humming
A.	increases
B.	decreases
C.	remains same
D.	increases to very high
Answer» B. decreases

Discussion

21.	If one of the transformers is removed from the bank of only delta-delta, then it behaves with 58% power delivery?
A.	True
B.	False
Answer» B. False

Discussion

22.	Open delta transformers can be obtained from
A.	delta-delta
B.	star-delta
C.	delta-star
D.	any of the mentioned
Answer» B. star-delta

Discussion

23.	The delta-delta connections are used in applications of
A.	large l.v. transformers
B.	small h.v. transformers
C.	large h.v. transformers
D.	small l.v. transformers
Answer» B. small h.v. transformers

Discussion

24.	The transformer which is more feasible to use in the distribution ends should be
A.	star-delta
B.	delta-star
C.	scott
D.	delta-delta
Answer» B. delta-star

Discussion

25.	Three units of single phase transformers and one single three-phase transformer rating
A.	will be same for one rating
B.	can never be made same
C.	may be same
D.	none of the mentioned
Answer» B. can never be made same

Discussion

26.	A V-V connected transformer can be connected in parallel to delta-delta connected transformer but not to
A.	delta-star
B.	star-delta
C.	star-V
D.	all of the mentioned
Answer» B. star-delta

Discussion

Explore topic-wise MCQs in Electrical Machines.

A recording of the output of the emf induced for star and delta are recorded. Then shape of the emf induced in Y-connected 3-phase transformer is non sinusoidal in nature due to ___________

While using three phase transformers, it is taken care about the third harmonics current in the system. This is present when transformer set is delta on either side.

A 400 V, 10 KVA transformer at 50 Hz, is operated at the frequency of 40 Hz, then the humming ___________

When we magnetize the ferromagnetic core of the transformer, core length_ and it when demagnetized.

If para magnetic core is used in the place of the ferromagnetic core of the transformer, then magnetostriction will ___________

Below is the circuit diagram for delta-delta transformer have a transformation ratio ‘k’. The current flowing in the windings of phase r-y in the below diagrams is?

If one of the transformers is removed from the bank of only delta-delta, then it behaves with 58% power delivery.

Open delta transformers can be obtained from ___________

The delta-delta connections are used in applications of ___________

The voltage across the terminal ‘r’ and ‘y’ is?

For the given circuit below, the voltage across the terminal ‘a’ and ‘b’ is?

The transformer which is more feasible to use in the distribution ends should be ___________

Three units of single phase transformers and one single three-phase transformer rating ___________

A V-V connected transformer can be connected in parallel to delta-delta connected transformer but not to ___________

When we magnetize the ferromagnetic core of the transformer, core length_ and it when demagnetized.$

If_para_magnetic_core_is_used_in_the_place_of_the_ferromagnetic_core_of_the_transformer,_then_magnetostriction_will$

Shape of emf generated by delta connected transformer is not always sinusoidal.

A recording of the output of the emf induced for star and delta are recorded.

While using three phase transformers, it is taken care about the third harmonics current in the system.

A 400 V, 10 KVA transformer at 50 Hz, is operated at the frequency of 40 Hz, then the humming

If one of the transformers is removed from the bank of only delta-delta, then it behaves with 58% power delivery?

Open delta transformers can be obtained from

The delta-delta connections are used in applications of

The transformer which is more feasible to use in the distribution ends should be

Three units of single phase transformers and one single three-phase transformer rating

A V-V connected transformer can be connected in parallel to delta-delta connected transformer but not to

Explore topic-wise MCQs in Electrical Machines.

A recording of the output of the emf induced for star and delta are recorded. Then shape of the emf induced in Y-connected 3-phase transformer is non sinusoidal in nature due to ___________

While using three phase transformers, it is taken care about the third harmonics current in the system. This is present when transformer set is delta on either side.

A 400 V, 10 KVA transformer at 50 Hz, is operated at the frequency of 40 Hz, then the humming ___________

When we magnetize the ferromagnetic core of the transformer, core length_______ and it ______ when demagnetized.

If para magnetic core is used in the place of the ferromagnetic core of the transformer, then magnetostriction will ___________

Below is the circuit diagram for delta-delta transformer have a transformation ratio ‘k’. The current flowing in the windings of phase r-y in the below diagrams is?

If one of the transformers is removed from the bank of only delta-delta, then it behaves with 58% power delivery.

Open delta transformers can be obtained from ___________

The delta-delta connections are used in applications of ___________

The voltage across the terminal ‘r’ and ‘y’ is?

For the given circuit below, the voltage across the terminal ‘a’ and ‘b’ is?

The transformer which is more feasible to use in the distribution ends should be ___________

Three units of single phase transformers and one single three-phase transformer rating ___________

A V-V connected transformer can be connected in parallel to delta-delta connected transformer but not to ___________

When we magnetize the ferromagnetic core of the transformer, core length_______ and it ______ when demagnetized.$

If_para_magnetic_core_is_used_in_the_place_of_the_ferromagnetic_core_of_the_transformer,_then_magnetostriction_will$

Shape of emf generated by delta connected transformer is not always sinusoidal.

A recording of the output of the emf induced for star and delta are recorded.

While using three phase transformers, it is taken care about the third harmonics current in the system.

A 400 V, 10 KVA transformer at 50 Hz, is operated at the frequency of 40 Hz, then the humming

If one of the transformers is removed from the bank of only delta-delta, then it behaves with 58% power delivery?

Open delta transformers can be obtained from

The delta-delta connections are used in applications of

The transformer which is more feasible to use in the distribution ends should be

Three units of single phase transformers and one single three-phase transformer rating

A V-V connected transformer can be connected in parallel to delta-delta connected transformer but not to

When we magnetize the ferromagnetic core of the transformer, core length_ and it when demagnetized.

When we magnetize the ferromagnetic core of the transformer, core length_ and it when demagnetized.$